1. Field of the Invention
The present invention pertains generally to the acoustical arts. More specifically, the present invention pertains to systems and methods to improve speech intelligibility in the presence of intermittent background noise. The present invention, in a preferred embodiment, is particularly but not exclusively, useful as a voice detection system and method for compensation thereof for automatic volume control devices; in addition to voice detection for remote acoustic monitors.
2. Description of the Prior Art
The automatic volume control (AVC) system and methods applicable to audio output devices such as a car radio are generally known. Similarly, AVCs for two-way communication devices, such as cellular phones are also generally known.
Cellular telephones, in particular, are often used outdoors in crowds, and in cars and other environments where the background noise fluctuates in intensity. To adjust the volume control constantly on a telephone in a noisy environment is inconvenient, and may even be impractical. For this reason, a user of a communications device such as a portable telephone could potentially benefit from an AVC feature.
The AVC for a telephone is similar to the AVC for a radio in that both should have some means of discriminating significant noise from less consequential noise. Both should also have some means of separating the significant noise from a signal that requires no compensation or different compensation. In the case of a radio, the signal that requires no compensation by an AVC is the normal audio output of the radio speakers. The AVC for a radio should have some means of separating the speaker signal from the noise background. In the case of a telephone, the signal that requires no compensation or different compensation than the noise background is the telephone user's own voice. The AVC for a telephone or other multiplexed communications device should have some means of separating the user's voice from the noise background. Accordingly, a problem arises since an AVC for a cellular phone should not adjust an amplifier gain based on the user's own voice. Also, cellular phones currently are configured with just one (voice) microphone, and therefore, a solution providing AVC for a cellular phone should consider both one (voice) microphone and two (voice and noise) microphones.
In light of the above, it is an object of the present invention to provide a solution for a system providing AVC in a two-way communication device as to how to deal with a situation wherein the user's own voice undesirably affects an AVC. It is further an object of the present invention to provide a solution that applies to a two-way device that has a single (voice) microphone; in addition to a solution that applies to a two-way device that has been configured with two microphones, namely a voice and a noise microphone. It is still further an object of the present invention to provide a method to discriminate a user's own voice from that of the background for a two-way device that employs both a voice microphone and a noise microphone.